With rapid development of communications technologies, Wideband Code Division Multiple Access (WCDMA, Wideband Code Division Multiple Access), which is one of the mainstream technologies of a third generation mobile communications system, is widely studied and used on a global scale. The current WCDMA has multiple versions, such as a release 99 version (R99, Release99), a release 4 version (R4, Release4), a release 5 version (R5, Release5), a release 6 version (R6, Release6), and a release 7 version (R7, Release7).
To improve a data transmission rate and meet different requirements, the WCDMA introduces a high speed uplink packet access (HSUPA, High Speed Uplink Packet Access) technology in the R6 version, thereby improving a transmission speed of an uplink link. The current HSUPA technologies are carried on a single frequency, that is, single-carrier data transmission.
To further improve a data transmission rate of the HSUPA system, the WCDMA introduces an uplink MIMO (Multiple-Input Multiple-Output, multiple-input multiple-output) technology in an R11 version. Compared with a system using a single antenna on an uplink, a system using multiple antennas can improve a transmission capability of a channel.
Maximum allowed transmit power of a user equipment (UE, User Equipment) is stipulated in WCDMA-related protocols. The UE needs to keep actual uplink transmit power lower than or equal to the maximum allowed transmit power. A carrier power control method for controlling the actual uplink transmit power of the UE in the prior art is as follows: calculating transmit power required by the UE to send a data transmission block to be sent on a carrier; and if the sum of the transmit power obtained through calculation and power of other uplink channels (that is total transmit power of the UE) exceeds the maximum allowed transmit power, performing power reduction for the carrier so that the transmit power of the UE is less than or equal to the maximum allowed transmit power. However, because only one data transmission block to be sent on the carrier is supported, the prior art cannot be applied to an uplink MIMO scenario and power control of the uplink MIMO cannot be implemented.